A 90-page handbook with no bookmark pane is a 90-page scroll. Readers give up around page 12.
Bookmarks turn a long PDF into something navigable — a tree of clickable headings that appears in every modern reader's sidebar. They're cheap to add and they radically change how usable your document feels.
Plan the hierarchy first
Bookmarks work best when they mirror the document's actual structure. For a report: top-level entries for each section, second-level for sub-sections, and stop there. Three levels deep is the practical limit before the sidebar becomes a maze.
Write the list out before you open the editor. "Executive Summary, Methodology, Findings (with three sub-points), Recommendations, Appendix" — that's the kind of skeleton you want.
Add bookmarks page by page
Open the document in Flint's editor, navigate to the page where a section starts, and add a bookmark with the section title. Repeat for each entry.
For nested entries, indent them under their parent — the editor supports drag-to-nest. Match the wording to the section heading exactly so readers don't second-guess where they're going.
Test the navigation in a real reader
Save the file and open it in Preview, Adobe Reader, or your browser's PDF viewer. The bookmark pane should appear on the left. Click each entry and confirm it lands on the right page.
If a bookmark points to the wrong page, you've probably reordered pages since adding it. Use reorder pages carefully — bookmarks tied to deleted or moved pages need to be rebuilt.
Pair bookmarks with a clickable contents page
Bookmarks live in the sidebar. A table-of-contents page lives inside the document. Together they cover both navigation styles — sidebar for power users, contents page for printed copies.
Add a table of contents page near the front and link each entry using internal hyperlinks. Long manuals especially benefit from this double-up.
FAQ
Do all PDF readers show bookmarks?
Yes. The bookmark pane is part of the PDF standard. Preview on Mac, Adobe Reader, Chrome's built-in viewer, and most mobile readers all show it — sometimes labelled "Outline" or "Contents".
Can I import bookmarks from a Word document's heading styles?
When you convert from Word, headings sometimes come through as bookmarks automatically. If they don't, convert Word to PDF first, then add bookmarks based on the heading structure.
How deep should I nest bookmarks?
Two or three levels max. Beyond that, readers can't see the whole structure without scrolling the sidebar, and the navigation aid becomes another thing to navigate.
Will bookmarks survive if someone re-saves the PDF?
In most readers, yes. Some "print to PDF" workflows strip them, though, so it's worth telling collaborators not to re-export the file unless they have to.
A bookmark tree is the cheapest usability upgrade a long PDF can get. Open your document in Flint's editor and turn the wall of pages into something readers can actually move through.